Kohler Command voltage regulator question - Help

I had two of these go in one day - on different machines. I haven't blown one up in 10 years. Nothing is different - haven't made any adjustments or changes to these machines (exmarks). Anyone have any ideas on why they blow? Just thought it was very odd. What usually causes these to blow anyway?

I just want to make sure that I treat the problem and not the symptom - thanks!

Are you sure it is not the battery? This heat will kill a battery fast. Remove the battery and put a charger and charge this up and then put the batteries back and check the voltage output.
By the way the voltage regulator will not put out if it does not get a minimum of 6 volts from the battery. If the battery is 100% dead the voltage regulator will not switch on

Invest a few bucks in a 12 rechargeable battery pack for jump starting.

I've replace two charging coils on briggs that were fried to a crisp--- jump started from a running pick up. Most small engine charging systems are under 20 amp systems. When you back feed the small engine from a 65 amp pickup alternator, bad things happen.

Invest a few bucks in a 12 rechargeable battery pack for jump starting.

I've replace two charging coils on briggs that were fried to a crisp--- jump started from a running pick up. Most small engine charging systems are under 20 amp systems. When you back feed the small engine from a 65 amp pickup alternator, bad things happen.

Thanks guys! I think I may have contributed to the issue by using a higher amp fuse than I probably should have. I put a 30amp fuse in the system when I believe I should have used a 20 amp (charging system is 15amp). A friend explained to me how this may have caused the problem.... however, that only explains one mower. I still have yet to figure out what may have happened with the other. Heat maybe ?